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Each box contains an injector pulsewidth. For this engine I disabled the boost compensation map (for the most part, it might still be adding 2% up top) This is from a 2jz-gte I tuned. It shows what you want, a 1-bar of boost pressure without a 100% VE increase to injector on-time due to an OEM camshaft restricting VE primarily. VE does not always correlate torque (you cannot always say peak VE = peak torque), since ignition timing can ruin torque output even when VE is good or getting better.
This isn't VE, this is fuel targeting (using injector pulse widths). This I would have to assume too many variables to calculate VE from, like what AFR is targeted, what AFR is actual, what PE adjustments are made (vs coolant temp and vs RPM), what fuel injectors are installed, etc.
And peak VE and peak TQ are directly tied. The relationship between the two are tied because the more air you take in the more power you can make (force over time and distance), and since power is relative to TQ (force) at RPM (time and distance) at the point the engine is taking in the highest amount of air it can, it will always peak TQ there too. It will not necessarily peak HP there because HP is a result of TQ AND RPM. TQ is a result of air flow.
Of course, if someone tuned the car wrong it could mess up the relationship between peak TQ and Peak VE. But I doubt that as peak TQ is a result of peak air flow. If someone messed up the timing or AFR's in the Peak VE range VE would be reduced (and therefore TQ), that would result in peak Torque and peak VE both being moved, together. In any case, I'm talking about optimally tuned engines for their given design and purpose.
This isn't VE, this is fuel targeting (using injector pulse widths).
The map does communicate engine VE by comparing pulsewidths between known ranges, like from from 0 to 15 psi. It moves from 3.2 to 4.8. Yes at 3.2 it was leaner than 11:1, and maybe there is 2% boost comp, and maybe another 1.5% from the TPS, and maybe .05% from my CTS, see how many variables start to play a role? But we can still make an observation about the move from 3.2 to 4.8, for example I can tell you for sure that VE did not double at 15psi of boost. This is information you will know when tuning YOUR engine, not mine, I am not assuming you know what engine this is for, I am not saying this is a VE graph, I am saying that if you DID have an engine to tune, and you DID have this kind of fuel map, these values would communicate engine VE to you as you run the engine and gain intuition about its behaviors, by comparing engine output and boost pressure with fuel use. As another example I know that if the engine receives a head/cam I will immediately need to raise the values inside those cells that say 4.8 to around 2(3.2) or 6.5 for starters because NOW I would be thinking about 200%VE, and that is the place where it is bound to show up.
And peak VE and peak TQ are directly tied.
saying they are tied is misleading. everything is tied to everything else, I can relate mice to hydrogen atoms, its all matter and light. Specifically, torque and VE cannot be correlated because as I said,
If someone messed up the timing or AFR's in the Peak VE range VE would be reduced (and therefore TQ)
Sorry, engine VE is a function of the engine spinning, even if we spin it with an electric motor, the engine VE will be the same. If I bring an engine to WOT and hold the RPM constant the way an engine dyno can, then retard the timing gradually, engine VE will remain constant while torque output drops, requiring less effort on behalf of the engine dyno to hold rpm constant while VE is staying nearly the same. If I spin the engine via electric motor the VE will remain constant at some RPM even though there is no torque being produced by it whatsoever. The two are not "tied" together the way you suggest.
Of course, if someone tuned the car wrong
everybody tunes cars wrong because no tune is perfect, and even if the number you install is perfect the computer is still imperfect. Put down 13.00 and get 13.0127 degrees followed by 13.005678 degrees followed by 12.99192472 degrees at the crankshaft. You think you are actually getting 13.00000 every single time? or exactly .0084 seconds of fuel as it pretends on a fuel map? The real number is NOT what you see. So part of tuning is intuition, knowing what the engine is doing and what to expect, and how to use the computers NON precise behaviors to an advantage for smoother engine operation or to make it more reliable, even in the face of its incorrectness, especially to unaware observers.
But I doubt that as peak TQ is a result of peak air flow
You also can't use the term peak airflow without specifying whether you mean peak mass per unit time or peak cylinder fill per unit time. Both are quantities of peak airflow but peak mass per unit time is horsepower while peak cylinder fill per unit time is peak torque. Injector duty is highest at peak mass per unit time, while pulsewidth is highest at peak cylinder fill per unit time.
Last edited by kingtal0n; Feb 12, 2016 at 02:40 AM.
I disagree with that....everything I've read point to both of them tracking very closely together....so to say that they don't correlate doesn't make sense.
Earl Scheib does the same thing. As far as pics are concerned, don't I remember reading where you said you owned a twin turbo setup? Yet then post random pics and all of the sudden it's a corporate "we" effort? Where's the pics of your pile?
Doesn't matter if you make 400 horsepower with head/cam or turbo, there is just as much "Stress incident" on that particular engine.
Your theory is completely dismissive of the specific structural and metallurgical limitations of the factory LT1 engine components, and also of the heat and additional cylinder pressure inevitably generated by forced induction, whether there is a charge cooling agent or not.
There are many, many LT1 cars out there with factory bottom ends making in excess of 400rwhp with ported heads/cam setups and lasting tens of thousands of daily driven hard miles. There are several on this forum currently and have been many more over the years.
You are not going to find many at all doing the same thing with the stock engine and a supercharger or turbocharger, and you'll likely find NONE that have lasted more than just a few thousand miles under boost.
The map does communicate engine VE by comparing pulsewidths between known ranges, like from from 0 to 15 psi. It moves from 3.2 to 4.8. Yes at 3.2 it was leaner than 11:1, and maybe there is 2% boost comp, and maybe another 1.5% from the TPS, and maybe .05% from my CTS, see how many variables start to play a role? But we can still make an observation about the move from 3.2 to 4.8, for example I can tell you for sure that VE did not double at 15psi of boost. This is information you will know when tuning YOUR engine, not mine, I am not assuming you know what engine this is for, I am not saying this is a VE graph, I am saying that if you DID have an engine to tune, and you DID have this kind of fuel map, these values would communicate engine VE to you as you run the engine and gain intuition about its behaviors, by comparing engine output and boost pressure with fuel use. As another example I know that if the engine receives a head/cam I will immediately need to raise the values inside those cells that say 4.8 to around 2(3.2) or 6.5 for starters because NOW I would be thinking about 200%VE, and that is the place where it is bound to show up.
Again, this is not a VE Table, I can determine VE from this table if I had A LOT more information; information I don't have.
11:1 was the lean point?! Holy ***** batman, how do you not see how much richer Turbo runs than NA? My RICH point in PE mode is 11.9:1, your leanest point is 8.6% richer than my richest point. And my richest point needs leaned out by 0.5-1:1.
saying they are tied is misleading. everything is tied to everything else, I can relate mice to hydrogen atoms, its all matter and light. Specifically, torque and VE cannot be correlated because as I said,
It's not misleading, it's factual.
Sorry, engine VE is a function of the engine spinning, even if we spin it with an electric motor, the engine VE will be the same. If I bring an engine to WOT and hold the RPM constant the way an engine dyno can, then retard the timing gradually, engine VE will remain constant while torque output drops, requiring less effort on behalf of the engine dyno to hold rpm constant while VE is staying nearly the same. If I spin the engine via electric motor the VE will remain constant at some RPM even though there is no torque being produced by it whatsoever. The two are not "tied" together the way you suggest.
If VE was purely a function of engine spinning it would get higher with higher RPM. It doesn't do that. It peaks much lower than peak RPM. If we spin it with an electric motor it's VE would be completely different than if it was running on fuel. You have to remember that airflow in the engine is pulsing and dynamic. Pulse waves, ignition timing, AFR's (burn rates), all change airflow characteristics inside an operating engine. If you change any of those, it will change how the air is flowing and how much TQ it can make at any given RPM. If you shift peak TQ, you shifted peak VE too. TQ is a RESULT of having the most amount of BMEP, that is a result of having the highest amount of air and fuel during a certain combustion cycle, which is a result of peak VE.
everybody tunes cars wrong because no tune is perfect, and even if the number you install is perfect the computer is still imperfect. Put down 13.00 and get 13.0127 degrees followed by 13.005678 degrees followed by 12.99192472 degrees at the crankshaft. You think you are actually getting 13.00000 every single time? or exactly .0084 seconds of fuel as it pretends on a fuel map? The real number is NOT what you see. So part of tuning is intuition, knowing what the engine is doing and what to expect, and how to use the computers NON precise behaviors to an advantage for smoother engine operation or to make it more reliable, even in the face of its incorrectness, especially to unaware observers.
Oh goodness. Do you really think this makes you sound smart? The only smart you're being right now is the verb. You'd have to be more than .0084 off on any and every aspect to make a marketable difference in peak VE/TQ.
You also can't use the term peak airflow without specifying whether you mean peak mass per unit time or peak cylinder fill per unit time. Both are quantities of peak airflow but peak mass per unit time is horsepower while peak cylinder fill per unit time is peak torque. Injector duty is highest at peak mass per unit time, while pulsewidth is highest at peak cylinder fill per unit time.
Peak VE dude, we're talking about peak VE. What the hell do you think I mean? I'm talking about a single 4 stroke event that has the highest Airflow during those 4 strokes compared to any other.
I disagree with that....everything I've read point to both of them tracking very closely together....so to say that they don't correlate doesn't make sense.
Greg Banish, in one of his books, closely compares the VE with the torque curve as well.
Do you build a VE table from a torque curve? No. However that does not mean that the two don't correlate.
This, I don't build VE tables from Torque tables, but by data logging and monitoring my AFR's and building my VE table from that. Then doing a dyno tune showed my peak TQ and peak VE are at the same RPM.
Earl Scheib does the same thing. As far as pics are concerned, don't I remember reading where you said you owned a twin turbo setup? Yet then post random pics and all of the sudden it's a corporate "we" effort? Where's the pics of your pile?
This, I don't build VE tables from Torque tables, but by data logging and monitoring my AFR's and building my VE table from that. Then doing a dyno tune showed my peak TQ and peak VE are at the same RPM.
The way I've learned to build a VE table from Banish's DVD, is to do roughly the following(once things like injectors are characterized, etc, etc,)...
Lock the PCM into speed density
Set all fueling targets to Lambda 1
Using a wideband to record Lambda data, setup a histogram plotted against the VE table to display Lambda error.
Run the engine in steady state on a load bearing dyno(locking the engine rpm and thus varying throttle..which moves you through the MAP ranges), record data for the fueling error in each of the VE cells.
Correct the VE table in each cell for the displayed fueling error.
Lather, rinse, repeat until you are within 3% error, then move to the next RPM point.
It was very eye opening for me to see this done. I appreciate the engineering angle he takes with tuning.
Part of Banish's VE building process can be seen at 10:44-11:44 with the Z06 on the dyno.
I have not got my Z28 on the dyno for "me" tuning it yet. I started to last year, by brushing up on all the stuff I've learned but life happened and I had to put those plans on hold. I'm picking back up on that project very soon though....I'll be logging my LT1's VE error with this.... http://www.palmerperformance.com/pro...shots/maps.png
I've been "blogging" over the years about my tuning journey here...and I've made mistakes along the way, but it's been a fun learning experience.....with plenty more journey to go. http://www.camaroz28.com/forums/comp...ts-lt1-770192/
The way I've learned to build a VE table from Banish's DVD, is to do roughly the following(once things like injectors are characterized, etc, etc,)...
Lock the PCM into speed density
Set all fueling targets to Lambda 1
Using a wideband to record Lambda data, setup a histogram plotted against the VE table to display Lambda error.
Run the engine in steady state on a load bearing dyno(locking the engine rpm and thus varying throttle..which moves you through the MAP ranges), record data for the fueling error in each of the VE cells.
Correct the VE table in each cell for the displayed fueling error.
Lather, rinse, repeat until you are within 3% error, then move to the next RPM point.
It was very eye opening for me to see this done. I appreciate the engineering angle he takes with tuning.
Part of Banish's VE building process can be seen at 10:44-11:44 with the Z06 on the dyno.
I have not got my Z28 on the dyno for "me" tuning it yet. I started to last year, by brushing up on all the stuff I've learned but life happened and I had to put those plans on hold. I'm picking back up on that project very soon though....I'll be logging my LT1's VE error with this.... http://www.palmerperformance.com/pro...shots/maps.png
I've been "blogging" over the years about my tuning journey here...and I've made mistakes along the way, but it's been a fun learning experience.....with plenty more journey to go. http://www.camaroz28.com/forums/comp...ts-lt1-770192/
Agreed, you must have all the constants and offsets dialed in before you can accurately measure AFR's to build up the VE tables.
When I did my VE tables, I locked out BLM locker and PE modes were set to zero. Then I reset all my BLM's. I'd drive for an hour, look at my log and adjust the VE tables based on BLMs in each cell, load the new tune, reset BLMs again and repeat. I'd smooth out the transitions between cells to after every adjustment. This took me a loooong time to do. Months to get it all dialed in.
I don't have that kind of access to a Dyno to load up each cell so I did what I could with what I have. Once I dialed in all my BLM cells, I took the car to a dyno and used a wideband to dial in PE modes. My PE tables are a bit skewed because I can't adjust my VE tables over 100%, to make up for that I used the PE tables to dial in the AFR target at WOT (I'm only at WOT when over 100% VE).
Now I wont go MAF mode because it's not calibrated for my engine any more (CAI, Cam,etc.). Next time I'm on the Dyno I'll have the PE Tables done in SD mode, then engage MAF mode and calibrate the MAF according to the Wideband. That should give me a very reliable tune.
This works out o.k. for now though. I still have a little bit of tweaking to do on my PE tables (lean it out a bit). But that can wait until after I get a 4" exhaust and my TB and Intake Done.
I grow tired of this. Everywhere you look, you find that turbochargers may improve economy, and they are working on advances to it i.e. steam turbocharging and direct injection techs to go along with it. I don't find a single paper saying otherwise, just you.
I must've missed this post of yours.
From the article you shared..... "Unfortunately for this comparison, the two engines aren’t available in Skodas with the same transmissions – the 2.0 FSI has a six-speed auto and the turbo 2.0 FSI a six-speed manual" They also fail to mention actual test vehicles used. I find that interesting and makes their credibility questionable at best, especially after what I found below.....
Not helping your argument. With the same transmission, it took a smaller boosted engine to beat the larger NA in fuel economy...... Hmmmm.....
A little more research shows that the FSI 2.0 (NA) get's 7.4L/100kM (31.8 US MPG) with A-95 fuel vs 7.9L/100kM (29.8 US MPG)for the TFSI (Turbo) 2.0 with A-98 (yes a higher rated octane fuel) in the same vehicle.
So officially rated, and not by someone writing an article with an agenda, the 2.0 NA gets better MPG than the Turbo variant, even with a different transmission and lower grade fuel.
I dont mind at all guys, learned some good stuff from this thread...sorry it took so long to get back to it
Ty McBride
Team Leader/Owner
McBride Motorsports
Ps...any companies out there I might not know about making quality Door Panel Inserts? Mine are fine as is, just wanting to upgrade my interior a bit. Thank you
I disagree with that....everything I've read point to both of them tracking very closely together....so to say that they don't correlate doesn't make sense.
Greg Banish, in one of his books, closely compares the VE with the torque curve as well.
Do you build a VE table from a torque curve? No. However that does not mean that the two don't correlate.
If you spin an engine with an electric motor, there will be some VE, not the same exact VE as when it was running, but we get this equation:
CID X rpm / 3456 = CFM
This equation implies CFM is a function of CID and RPM, not if the engine is running or not.
therefore, you can have a VE from 0 to 100% without a running engine (0 torque), the two share a domain function but are not directly correlated. Tuners might talk about them together (I often do) but specifically, they are independant functions. The word correlate is confusing because everything is correlated, mice and atoms, sun and gravity.
Originally Posted by SS RRR
Earl Scheib does the same thing. As far as pics are concerned, don't I remember reading where you said you owned a twin turbo setup? Yet then post random pics and all of the sudden it's a corporate "we" effort? Where's the pics of your pile?
I built a twin turbo V8 setup in my backyard when I was 17 years old for less than $500 after building a forged engine and 700R4 for it. PM me for pics and details (anyone). This is the old site http://www.geocities.ws/kingtaling/turbo.html
I still have all the pics.
Originally Posted by HellTeeOne
Your theory is completely dismissive of the specific structural and metallurgical limitations of the factory LT1 engine components, and also of the heat and additional cylinder pressure inevitably generated by forced induction, whether there is a charge cooling agent or not.
There are many, many LT1 cars out there with factory bottom ends making in excess of 400rwhp with ported heads/cam setups and lasting tens of thousands of daily driven hard miles. There are several on this forum currently and have been many more over the years.
You are not going to find many at all doing the same thing with the stock engine and a supercharger or turbocharger, and you'll likely find NONE that have lasted more than just a few thousand miles under boost.
I never posted a theory, a theory needs graphs and data points to be accepted backed by years of supplementary research. I only said that if we have X number of air molecules, the piston will fail, whether it was there due to low temperature or forced induction at higher temperature, or visca versa, high temp on a natural aspirated engine, low temp on a forced induction engine. The high temp is only an issue when fuel quality is poor, whether forced inducted or not, resulting in a damaging pressure wave which fragments the piston. There is more than one way to kill a piston, we can use race fuel in a naturally aspirated engine and still ruin a piston.
Originally Posted by hrcslam
If VE was purely a function of engine spinning it would get higher with higher RPM. It doesn't do that.
Peak VE dude, we're talking about peak VE. What the hell do you think I mean? I'm talking about a single 4 stroke event that has the highest Airflow during those 4 strokes compared to any other.
You can't assume people know "what you mean". Be very specific; if you mean airflow per unit time, then say it. If you meant peak cylinder fill, then say it. Saying "airflow" arbitrarily is a unit-less, description less, a flawed expression. Also, during an exhaust stroke, there is potential to flow more air through the cylinder than during the intake stroke.
Now, as to a function on a running engine of VE, here is a function of VE:
VE = (CFM * 3456) / (CID * RPM)
As you can see, RPM must be > 0 for there to be engine VE. Therefore, engine VE is a function of a spinning engine. I politely recommend more math courses.
Last edited by kingtal0n; Feb 21, 2016 at 03:26 PM.
I built a twin turbo V8 setup in my backyard when I was 17 years old for less than $500 after building a forged engine and 700R4 for it. PM me for pics and details (anyone). This is the old site http://www.geocities.ws/kingtaling/turbo.html
I still have all the pics.
This is your thread now. Post them up. How difficult does it need to be to follow a simple request?
If you spin an engine with an electric motor, there will be some VE, not the same exact VE as when it was running, but we get this equation:
CID X rpm / 3456 = CFM
This equation implies CFM is a function of CID and RPM, not if the engine is running or not.
therefore, you can have a VE from 0 to 100% without a running engine (0 torque), the two share a domain function but are not directly correlated. Tuners might talk about them together (I often do) but specifically, they are independant functions. The word correlate is confusing because everything is correlated, mice and atoms, sun and gravity.
An electric motor does not have jack squat to do with the statement you made on the VE and torque curves not correlating. They do...you know it and you don't have the ***** to say you made a mistake.
You are trying to shift around the subjects after being called on the carpet for such a silly statement. You write a book on what could be said in less than a paragraph trying to look smart, but instead it comes off as making you look desperate.
There is no shame in saying "Oops, I made a mistake. My bad." I've done it more times than I can count....and I do it not just to remain credible, but because it's the right thing to do.
So do yourself a favor and stop trying so hard to make yourself look right all the time, because you are not. Now, learn to deal with it in the right way other than trying to bait and switch the topics.
If you spin an engine with an electric motor, there will be some VE, not the same exact VE as when it was running, but we get this equation:
CID X rpm / 3456 = CFM
This equation implies CFM is a function of CID and RPM, not if the engine is running or not.
therefore, you can have a VE from 0 to 100% without a running engine (0 torque), the two share a domain function but are not directly correlated. Tuners might talk about them together (I often do) but specifically, they are independant functions. The word correlate is confusing because everything is correlated, mice and atoms, sun and gravity.
I built a twin turbo V8 setup in my backyard when I was 17 years old for less than $500 after building a forged engine and 700R4 for it. PM me for pics and details (anyone). This is the old site http://www.geocities.ws/kingtaling/turbo.html
I still have all the pics.
I never posted a theory, a theory needs graphs and data points to be accepted backed by years of supplementary research. I only said that if we have X number of air molecules, the piston will fail, whether it was there due to low temperature or forced induction at higher temperature, or visca versa, high temp on a natural aspirated engine, low temp on a forced induction engine. The high temp is only an issue when fuel quality is poor, whether forced inducted or not, resulting in a damaging pressure wave which fragments the piston. There is more than one way to kill a piston, we can use race fuel in a naturally aspirated engine and still ruin a piston.
You can't assume people know "what you mean". Be very specific; if you mean airflow per unit time, then say it. If you meant peak cylinder fill, then say it. Saying "airflow" arbitrarily is a unit-less, description less, a flawed expression. Also, during an exhaust stroke, there is potential to flow more air through the cylinder than during the intake stroke.
Now, as to a function on a running engine of VE, here is a function of VE:
VE = (CFM * 3456) / (CID * RPM)
As you can see, RPM must be > 0 for there to be engine VE. Therefore, engine VE is a function of a spinning engine. I politely recommend more math courses.
I did say "PURELY", you know to be techinically accurate and all that.....
It does seem the only one oblivious to what I'm saying here is you....
Sounds like the only one here needing to gain some knowledge is you. May I suggest basic physics as a starting point? Follow that with some reading comprehension..... No, flip that. Reading comprehension first, then basic physics.
I have an opportunity to pick up a CC503 cam. I had one ages ago but someone ripped off my garage and took off with my LE2 Heads...and shortly after I was sweating my nuts off in the sandbox. I am still planning on going with some LE2's. I wouldn't install the cam until I received the LE2's of course. Do you think his head would work well with the 503 cam sepcs or should I wait and order one of his custom grinds. This cam is new in the box and my friend told me he'd give it up for 50$. I'm also prepping for the race season and my NASA Super Unlimited Series car is eating a big chunk of my change so saving money is a big one. Thanks guys stay frosty, watch for tard drivers
If you have spare cash for a cam swap, why not? Hell, flip it on ebay or here and put money in your pocket. Depends on your goals if you should get an le cam though.
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stay frosty, watch for tard drivers